Central nervous system /certified fixed orthodontic courses by Indian dental academy


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Central nervous system /certified fixed orthodontic courses by Indian dental academy

  1. 1. CENTRAL NERVOUS SYSTEM INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Pathology of the Nervous System Introduction  Increased intracranial pressure  Vascular and circulatory disorders  Trauma  Infections  Tumors  Demyelinating diseases  Degenerative diseases  Developmental Abnormalities  www.indiandentalacademy.com
  3. 3. Hematoxylin and Eosin Luxol fast-blue-PAS Bielschowsky www.indiandentalacademy.com
  4. 4. Cell types 1. 2. 3. 4. 5. Neuron: functions in neural transmission, most vulnerable cell, limited regeneration Astrocyte: major reactive cell of CNS forms ‘scar’ Oligodendrocyte: highly vulnerable, limited proliferation, forms myelin sheath Ependymal cell: vulnerable, limited regeneration, lines ventricles (ependymal granulations) Microglial cell: monocyte/macrophage (bone marrow) derived phagocytic cell, antigen presentation, producer of cytokines, inflammatory cell www.indiandentalacademy.com
  5. 5. Introduction  Cellular reactions of the central nervous system  Neurons: permanent  Axonal retraction (axonal spheroids)  Ischemic cell changes  Atrophy and degeneration  Intraneuronal deposits and inclusions (neurodegenerative diseases)  Glia: proliferate, form glial ‘scar’ www.indiandentalacademy.com
  6. 6. Gray Matter www.indiandentalacademy.com
  7. 7. Nissl substance www.indiandentalacademy.com
  8. 8. White Matter www.indiandentalacademy.com
  9. 9. Ventricular lining www.indiandentalacademy.com
  10. 10. Mechanisms of dysfunction causing disease  Pathophysiological (toxic/metabolic)  Structural  Focal lesions correlate with localizing symptoms  System degenerations correlate with functionally localizing symptoms (ie motor neuron disease)  Increased intracranial pressure (generalized or focal), can cause global symptoms or brain herniation since the volume of the brain is fixed by the skull www.indiandentalacademy.com
  11. 11. Increased intracranial pressure Headache Vomiting Decreased Level of Consciousness Papilledema Herniation www.indiandentalacademy.com
  12. 12. Causes of Cerebral Edema  Generalized (frequently cytotoxic)  Hypoxia  Toxins  Encephalitis  Trauma  Focal (often vasogenic)  Infarction  Injury/contusion  Mass—neoplastic, infectious (cerebral abscess), hematoma www.indiandentalacademy.com
  13. 13. TYPES OF HERNIATION 1. 2. 3. 4. Subfalcine (cingulate) Transtentorial (uncal) Tonsillar (foramen magnum) Extracranial www.indiandentalacademy.com
  14. 14. TRANSTENTORIAL (UNCAL) HERNIATION SHIFT OF THE BRAIN FROM THE MIDDLE TO THE POSTERIOR FOSSA THROUGH THE TENTORIAL INCISURA MAY BE UNILATERAL OR “CENTRAL” SECONDARY EFFECTS INCLUDE: Compression of the third cranial nerve(s) Duret hemorrhages in midline rostral brainstem Compression of the contralateral cerebral peduncle (Kernohan’s notch) Compression of the posterior cerebral artery with infarction of the medial occipital lobe www.indiandentalacademy.com
  15. 15. UNCAL HERNIATION Normal uncus Herniated right uncus www.indiandentalacademy.com
  16. 16. DURET HEMORRHAGES Midline Duret hemorrhages plus Kernohan’s notch in the right cerebral peduncle www.indiandentalacademy.com
  17. 17. HYDROCEPHALUS DILATATION OF THE VENTRICULAR SYSTEM NONCOMMUNICATING: Due to obstruction within the ventricular system, e.g., tumor, aqueductal stenosis COMMUNICATING: Due to obstruction of CSF flow in the subarachnoid space with decreased reabsorption www.indiandentalacademy.com
  18. 18. CSF FLOW www.indiandentalacademy.com
  19. 19. COMMUNICATING HYDROCEPHALUS Dilatation of the entire ventricular system including the aqueduct and fourth ventricular foramina. There is thickening and scarring of the meninges, secondary to previous subarachnoid hemorrhage www.indiandentalacademy.com
  20. 20. Summary: Microscopic and gross brain abnormalities   Cell types: Function and proliferative capacity Mechanisms of CNS dysfunction: Pathophysiological “invisible” lesions: metabolic, toxic  Structural “visible” abnormalities: mass, edema, hydrocephalus, cytologic abnormalities.   Increased intracranial pressure Causes of cerebral edema: focal and generalized  Types of herniation: cingulate, uncal, tonsillar  Hydrocephalus: non-communicating and communicating  www.indiandentalacademy.com
  21. 21. Vascular and Circulatory Disorders Ischemia/Infarction Transient Ischemic Attacks Hemorrhage www.indiandentalacademy.com
  22. 22. Stroke: Ischemia/Infarct Atherosclerosis: Narrowing  Thrombosis: Damages vessel, infarcts are non-hemorrhagic  Embolism: Heart valves, plaques (frequently hemorrhagic)  Vasospasm: Rare, but common after subarachnoid hemorrhage  Hypertensive vasculopathy: Lacunar infarcts  www.indiandentalacademy.com
  23. 23. RISK FACTORS atherosclerosis www.indiandentalacademy.com
  24. 24. RISK FACTOR: atherosclerosis www.indiandentalacademy.com
  25. 25. EMBOLIC INFARCTS TYPICALLY ARE HEMORRHAGIC www.indiandentalacademy.com
  26. 26. RISK FACTORS: hypertension (lacunar infarcts) Lacunar infarct of the pons Lacunar infarct of the globus pallidus www.indiandentalacademy.com
  27. 27. Other causes of ischemia    Systemic Hypotension: Results in watershed infarcts Hypoxia or Anoxia: Lack of oxygen or poor perfusion after MI results in watershed infarcts and/or damage in vulnerable regions, ie hippocampus and cerebellum Venous thrombosis: Rare, causes hemorrhagic infarcts, consider coagulopathy www.indiandentalacademy.com
  29. 29. VASCULAR WATERSHEDS www.indiandentalacademy.com
  30. 30. VENOUS CIRCULATION www.indiandentalacademy.com
  31. 31. VENOUS INFARCTION    Venous infarction usually results from venous sinus thrombosis Risk factors include a number of states that result in hyperviscosity or increased coagulability Grossly they are very hemorrhagic www.indiandentalacademy.com
  32. 32. Transient Ischemic Attacks  Lasts less than 24 hours by definition  Attributed to transient embolization  Occurs in patients with atherosclerotic stenosis  Harbinger of cerebral infarction www.indiandentalacademy.com
  33. 33. Summary: Strokes due to ischemia/infarction        Large vessel atherosclerotic disease (nonhemorrhagic) Embolic (hemorrhagic) Hypertensive (hemorrhages and lacunes) Vasospasm (2° to subarachnoid hemorrhage) Watershed infarcts: hypotension and hypoxia Venous thrombosis (rare, hemorrhagic) TIA: clears in 24 hours -by definition, often associated with large vessel disease www.indiandentalacademy.com
  34. 34. Strokes Due to Hemorrhage Hypertension Aneurysms Vascular Malformations Bleeding Diathesis Trauma www.indiandentalacademy.com
  35. 35. HYPERTENSIVE HEMORRHAGE lenticulostriate arteries www.indiandentalacademy.com
  36. 36. SACCULAR ANEURYSMS www.indiandentalacademy.com
  37. 37. SUBARACHNOID HEMORRHAGE rupture of saccular (berry) aneurysm www.indiandentalacademy.com
  38. 38. MYCOTIC ANEURYSM (bacterial) www.indiandentalacademy.com
  39. 39. VASCULAR MALFORMATION AS A SOURCE OF HEMORRHAGE arteriovenous malformation (AVM) www.indiandentalacademy.com
  40. 40. BLOOD DYSCRASIAS AS A CAUSE OF HEMORRHAGE thrombocytopenia www.indiandentalacademy.com
  41. 41. Summary: Strokes due to hemorrhage   Hypertension: Most common cause of brain hemorrhage, sites include basal ganglia, pons, cerebellum and cerebral white matter Aneurysms: Berry aneurysm: Most common type, causes SAH  Mycotic aneurysm: Rare, parenchymal bleed, bacterial  Atherosclerotic: Rarely bleed, may cause mass effect, fusiform   Vascular malformations and clotting abnormalities www.indiandentalacademy.com
  42. 42. Closed Head Injury Concussion  Immediate and temporary disturbance of brain function.   Cause   Grading (1. mild: no LOC/smpt <15 min, 2. mod: no LOC/smpt >15min, 3. severe: any LOC) Shearing of axons Signs: Amnesia, confusion, headache, visual disturbances, nausea, vomiting, dizziness www.indiandentalacademy.com
  43. 43. Closed Head Injury    Epidural hematoma: Middle meningeal artery tear (temporal bone fracture), accumulates rapidly (arterial) Subdural hematoma: Shearing of bridging veins, accumulate in hours to days (rarely weeks+) Subarachnoid hemorrhage: Occurs with contusions or intraparenchymal hemorrhage (also with berry aneurysms) www.indiandentalacademy.com
  44. 44. TRAUMA AS A CAUSE OF HEMORRHAGE subdural hematoma www.indiandentalacademy.com
  45. 45. Closed Head Injury     Contusions: Brain against bone, coup (at site of impact)/contrecoup (side opposite impact) Intracerebral hemorrhage: Shearing of brain vessels, high impact Diffuse Axonal Injury: Shearing of axons results in post-traumatic neurologic deficits Cerebral Edema: Occurs with and without an obvious structural lesion  Note: Can occur without evidence of hemorrhage www.indiandentalacademy.com
  46. 46. TRAUMA AS A CAUSE OF HEMORRHAGE: contusions www.indiandentalacademy.com
  47. 47. Other traumatic injuries   Penetrating injuries: Bullets, bone fragments, result in laceration with the potential for infection Spinal cord injury: Fractures, vertebral dislocation, penetrating injury, the spinal cord may be crushed or the site of hemorrhage www.indiandentalacademy.com
  48. 48. Summary: Trauma   Closed head injuries:  Sites (epidural, subdural, subarachnoid, parenchymal) and typical etiology  Contusion, hemorrhage, diffuse axonal injury, edema Penetrating injuries:  Causes and risks (infection)  Spinal cord injuries www.indiandentalacademy.com
  49. 49. Infections  Meningitis  Cerebral abscess Bacterial  Subdural Tuberculous empyema  Cerebritis  Viral encephalitis Fungal Viral www.indiandentalacademy.com
  50. 50. Infections: Route of entry  Hematogenous (most common) Localized source: abscess, heart valve, lung infection  Other: mosquitos, needles     Direct implantation (trauma) Local extension (ear infection abscess) Axonal transport (rabies, HSV) www.indiandentalacademy.com
  51. 51. Meningitis  Inflammation of the meninges Fever  Headache  Stiff neck  Decreased level of consciousness     Bacterial (purulent) Tuberculous (granulomatous) Fungal (granulomatous) www.indiandentalacademy.com
  52. 52. Bacterial Meningitis     Neonates: E. Coli, group B streptococci Infants and children: Hemophilus influenza (before immunization) Young adults: Neisseria meningitidis Adults: Streptococcus pneumoniae and Listeria monocytogenes www.indiandentalacademy.com
  53. 53. Meningitis: CSF findings  Increased white blood cells  Neutrophils with bacterial meningitis  Mononuclear cells (lymphocytes and macrophages) with TB and fungal infections  Lymphocytes with viral infection Increased protein (mild with viral)  Reduced glucose with bacterial meningitis  www.indiandentalacademy.com
  54. 54. PURULENT (BACTERIAL) MENINGITIS www.indiandentalacademy.com
  55. 55. PURULENT MENINGITIS www.indiandentalacademy.com
  56. 56. GRANULOMATOUS MENINGITIS: tuberculosis www.indiandentalacademy.com
  57. 57. GRANULOMATOUS MENINGITIS tuberculosis H&E Acid Fast www.indiandentalacademy.com
  58. 58. GRANULOMATOUS MENINGITIS tuberculosis Sequelae: Vasculitis Small infarcts Cranial neuropathies www.indiandentalacademy.com
  59. 59. ASEPTIC (VIRAL) MENINGITIS www.indiandentalacademy.com
  60. 60. Cerebral Abscess       Localized (contained) infection Hematogenous spread (heart valves), penetrating wound, paranasal sinuses, middle ear Oral flora may be the source of an abscess after dental manipulation Organisms are mixed and frequently anaerobic Surrounding cerebral edema is common CSF is frequently sterile www.indiandentalacademy.com
  61. 61. PURULENT CEREBRAL ABSCESS www.indiandentalacademy.com
  62. 62. Cerebritis in Immune-compromised Patients  Fungal Infections Aspergillus  Candida  Mucor   Protozoal Toxoplasma  Ameba infections can be seen in immunocompromised patients and rarely non-immunocompromised individuals  www.indiandentalacademy.com
  63. 63. Viral infection  Route of entry May be blood borne, respiratory or fecal/oral  Rabies-peripheral nerve   Acute viral encephalitis Herpes-activation of latent infection  Arbovirus-mosquito borne (West Nile virus)  Polio-enteric virus with neuronal tropism  Immunocompromised hosts  CMV  HSV/VZV  PML  HIV encephalitis (HIVE) www.indiandentalacademy.com 
  64. 64. ACUTE (VIRAL) ENCEPHALITIS microscopic features Lymphocytic infiltrates Microglial proliferation with microglial nodules www.indiandentalacademy.com
  65. 65. ACUTE (VIRAL) ENCEPHALITIS Herpes simplex www.indiandentalacademy.com
  66. 66. OPPORTUNISTIC VIRAL INFECTIONS: Progressive multifocal leukoencephalopathy (JC virus) www.indiandentalacademy.com
  67. 67. Progressive multifocal leukoencephalopathy www.indiandentalacademy.com
  68. 68. OPPORTUNISTIC INFECTIONS: Toxoplasmosis www.indiandentalacademy.com
  69. 69. OPPORTUNISTIC INFECTIONS: Toxoplasmosis Bradyzoites with cysts www.indiandentalacademy.com
  70. 70. OPPORTUNISTIC INFECTIONS Toxoplasmosis Necrotizing lesion H&E Immunoperoxidase for Toxo. tachyzoites www.indiandentalacademy.com
  71. 71. OPPORTUNISTIC INFECTIONS Fungal cerebritis : Aspergillus www.indiandentalacademy.com
  72. 72. OPPORTUNISTIC INFECTIONS Fungal cerebritis : Aspergillus www.indiandentalacademy.com
  73. 73. Summary: Infections     Meningitis: Definition, CSF findings Abscess: Definition, etiology Viral meningitis: Routes of entry (arbomosquitos) Viral encephalitis: Rabies, HSV, arboviruses   Spinal cord: Polio Infections in immunocompromised hosts Cerebritis: Fungal (aspergillus, protozoaltoxoplasma)  Viral: CMV, VZV, PML, Aids encephalopathy  www.indiandentalacademy.com
  74. 74. Primary Tumors of the Central Nervous System Glioma Astrocytoma Oligodendroglioma Ependymoma  Neuronal lineage  Meningioma  Nerve Sheath Tumors www.indiandentalacademy.com
  75. 75. Primary brain tumors: Cell types 1. 2. 3. 4. 5. 6. Neuron: Gangliocytoma, ganglioglioma medulloblastoma Astrocyte: Astrocytoma, glioblastoma Oligodendrocyte: Oligodendroglioma Ependymal cell: Ependymoma Microglial cell: Tumors derived from microglial cells have not been described. Meningeal cell: Meningiomas are derived from arachnoidal cells and are usually dural-based. www.indiandentalacademy.com
  77. 77. Gliomas      Diffusely infiltrating (not easily resected) Histologic appearance (grade) correlates with overall survival May become more malignant (higher grade) over time (especially astrocytomas which become glioblastomas) May spread via CSF Rarely (never) metastasize www.indiandentalacademy.com
  78. 78. JUVENILE PILOCYTIC ASTROCYTOMA www.indiandentalacademy.com
  79. 79. JUVENILE PILOCYTIC ASTROCYTOMA Rosenthal fibers Eosinophilic granular bodies www.indiandentalacademy.com
  80. 80. ASTROCYTOMA www.indiandentalacademy.com
  81. 81. ASTROCYTOMA www.indiandentalacademy.com
  82. 82. ASTROCYTOMA www.indiandentalacademy.com
  83. 83. ASTROCYTOMA FEATURES OF ANAPLASIA vascular proliferation www.indiandentalacademy.com
  84. 84. GLIOBLASTOMA MULTIFORME www.indiandentalacademy.com
  85. 85. GLIOBLASTOMA MULTIFORME www.indiandentalacademy.com
  86. 86. OLIGODENDROGLIOMA www.indiandentalacademy.com
  87. 87. EPENDYMOMA www.indiandentalacademy.com
  88. 88. Non-glial tumors    Medulloblastoma: Malignant cerebellar tumor of childhood Meningioma: Benign, superficial, wellcircumscribed tumor derived from arachnoidal cells Nerve sheath tumors: Schwannoma and neurofibroma, well-circumscribed, encapsulated tumors involving cranial nerves, spinal nerves and other peripheral nerves www.indiandentalacademy.com
  89. 89. MEDULLOBLASTOMA www.indiandentalacademy.com
  90. 90. MEDULLOBLASTOMA www.indiandentalacademy.com
  91. 91. MENINGIOMA www.indiandentalacademy.com
  92. 92. SCHWANNOMA www.indiandentalacademy.com
  93. 93. NEUROFIBROMA www.indiandentalacademy.com
  94. 94. Secondary Involvement of the Central Nervous System  Metastatic tumor  Melanoma  Renal cell  Lung  Contiguous involvement (pituitary adenoma and craniopharyngioma) www.indiandentalacademy.com
  95. 95. METASTATIC TUMORS leptomeningeal carcinomatosis www.indiandentalacademy.com
  96. 96. METASTATIC MELANOMA www.indiandentalacademy.com
  97. 97. PRIMARY CNS LYMPHOMA www.indiandentalacademy.com
  98. 98. Summary: Brain tumors     Primary brain tumors: glia (low grade vs. high grade), neurons, meninges Nerve sheath tumors: schwannoma and neurofibroma Secondary brain tumors: Metastatic (lung-males, breast-females, melanoma, renal cell carcinoma) Tumors arising outside the CNS with CNS symptoms: pituitary adenoma, craniopharyngioma www.indiandentalacademy.com
  99. 99. DISEASES OF MYELIN AND PERIPHERAL NERVE www.indiandentalacademy.com
  100. 100. MYELIN PNS MYELIN CNS MYELIN www.indiandentalacademy.com
  101. 101. CNS MYELIN oligodendrocytes www.indiandentalacademy.com
  102. 102. DISEASES OF MYELIN     DEMYELINATING DISEASES: Acquired disorders of myelin, such as multiple sclerosis. DYSMYELINATING DISEASES: Genetic disorders of myelin and its turnover, such as leukodystrophies www.indiandentalacademy.com
  103. 103. MULTIPLE SCLEROSIS  Multiple sclerosis is the most common disease of CNS myelin; prevalence of 1:1000.     Central nervous system myelin is selectively destroyed (axons are relatively preserved) Onset is frequently in 30 and 40 year old age groups. The disease is typically progressive with relapsing and remitting accumulations of focal neurologic deficits. The etiology is thought to be autoimmune in nature www.indiandentalacademy.com
  104. 104. MULTIPLE SCLEROSIS PLAQUES www.indiandentalacademy.com
  105. 105. MULTIPLE SCLEROSIS PLAQUE www.indiandentalacademy.com
  106. 106. MULTIPLE SCLEROSIS PLAQUES optic chiasm www.indiandentalacademy.com
  107. 107. MULTIPLE SCLEROSIS PLAQUES www.indiandentalacademy.com
  108. 108. PONTINE MS PLAQUE adjacent sections for myelin and axons  Luxol fast-blue-PAS Bielschowsky www.indiandentalacademy.com
  109. 109. MULTIPLE SCLEROSIS PLAQUE sharp circumscription www.indiandentalacademy.com
  110. 110. ACUTE DISSEMINATED ENCEPHALOMYELITIS  Post- or parainfectious encephalomyelitis:   following a viral infection Postvaccinial encephalomyelitis: Pasteur rabies and smallpox vaccination  Akin to EAE (experimental allergic enceph.)    ADE is an acute, monophasic illness Pathology:   Perivenous lymphocytic infiltrates with demyelination Autoimmune mechanism www.indiandentalacademy.com
  111. 111. ACUTE DISSEMINATED ENCEPHALOMYELITIS (ADEM) H&E Myelin basic protein IHC www.indiandentalacademy.com
  112. 112. ACUTE DISSEMINATED ENCEPHALOMYELITIS (ADEM) www.indiandentalacademy.com
  113. 113. Myasthenia Gravis  An autoimmune neuromuscular disease that results from autoantibodies at the neuromuscular junction.     Characterized by variable weakness of voluntary muscles (eye muscles may be weak) Worsens with activity (and late in the day) May be associated with other autoimmune disorders such as thyroid disease, rheumatoid arthritis and SLE Often associated with a thymoma, removal of the thymoma may be curative. www.indiandentalacademy.com
  114. 114. LEUKODYSTROPHIES    CLINICAL: A variety of inherited diseases with variable age of onset (usually in childhood) and rate of progression, which typically result in diffuse severe dysfunction. PATHOGENESIS: Recessive mutations in proteins related to myelin structure or metabolism The peripheral nervous system also may be involved in a number of forms www.indiandentalacademy.com
  115. 115. PATHOLOGY OF LEUKODYSTROPHIES    Demyelination in large confluent foci within the cerebral hemispheres and other sites GENERAL: 1. Loss of myelin and oligodendroglia 2. Relative preservation of axons DISEASE SPECIFIC: 1. Globoid cells (Krabbe’s disease) 2. Metachromatic material in macrophages and neurons (metachromatic leukodystrophy, aryl sulfatase deficient) 3. Adrenal atrophy and cytosomal inclusions (ALD, peroxisomal abnormality) www.indiandentalacademy.com
  116. 116. METACHROMATIC LEUKODYSTROPHY www.indiandentalacademy.com
  117. 117. METACHROMATIC LEUKODYSTROPHY sparing of subcortical arcuate fibers www.indiandentalacademy.com
  118. 118. METACHROMATIC LEUKODYSTROPHY (aryl sulfatase deficiency) Acidified cresyl violet metachromasia www.indiandentalacademy.com LFB-PAS
  119. 119. ADRENOLEUKODYSTROPHY www.indiandentalacademy.com
  120. 120. ADRENOLEUKODYSTROPHY lymphocytic infiltrates www.indiandentalacademy.com
  121. 121. KRABBE’S DISEASE (GLOBOID CELL LEUKODYSTROPHY) cerebroside-β-galactosidase deficiency www.indiandentalacademy.com
  122. 122. DISEASES OF PERIPHERAL NERVE CLASSIFICATION BY PATHOLOGY Demyelinating neuropathies Guillain-Barre-Landry syndrome Chronic inflammatory demyelinating polyneuropathy (CIDP) Axonal neuropathies: most neuropathies are axonal but pathology often is nonspecific Examples include hypertrophic neuropathies, herpes zoster, HIV, alcoholic and diabetic neuropathies www.indiandentalacademy.com
  123. 123. DEMYELINATING NEUROPATHY GUILLAIN-BARRE-LANDRY LFB-PAS Silver stain www.indiandentalacademy.com
  124. 124. DEMYELINATING NEUROPATHY GUILLAIN-BARRE-LANDRY inflammatory demyelination www.indiandentalacademy.com
  125. 125. DEMYELINATING NEUROPATHY GUILLAIN-BARRE-LANDRY evidence of remyelination www.indiandentalacademy.com
  126. 126.    Summary: Demyelinating/Dysmyelinating diseases Demyelinating disease: most common is MS, acute disseminated encephalomyelitis (rare, follows viral infection, vaccination) Leukodystrophies: Genetic diseases (many enzyme abnormalities are defined) resulting in myelin loss, occur early in life. Peripheral nerve demyelination: Guillain-Barre Syndrome, autoimmune, potential for remyelination with complete recovery www.indiandentalacademy.com
  127. 127. Neurodegenerative diseases Dementia: Alzheimer’s disease, Pick’s disease Movement Disorders: Parkinson’s disease, Huntington’s disease, Multiple Systems Atrophy Motor Disease: ALS, Werdnig-Hoffman, Poliomyelitis Prion disease www.indiandentalacademy.com
  128. 128. Alzheimer’s disease: Clinical features  Clinical features of dementia  Impairment of recent memory  Aphasia (naming), apraxia (motor), agnosia (object), executive functioning  Impaired level of function  Progressive over time  47% of people over 85 years of age are affected www.indiandentalacademy.com
  129. 129. Alzheimer’s disease: Pathogenesis The amyloid hypothesis: Abnormal APP processing leads to deposits of insoluble B-pleated amyloid protein  www.indiandentalacademy.com
  130. 130. Alzheimer’s disease: Gross and microscopic features Gross brain atrophy: neuronal loss  Neuritic (senile) plaques containing Bamyloid  Neurofibrillary tangles composed of phosphorylated microtubule associated tau protein  Cerebral amyloidosis  www.indiandentalacademy.com
  131. 131. www.indiandentalacademy.com
  132. 132. www.indiandentalacademy.com
  133. 133. www.indiandentalacademy.com
  134. 134. www.indiandentalacademy.com
  135. 135. www.indiandentalacademy.com
  136. 136. Other Dementias  Dementia with Lewy bodies Second most common neurodegenerative cause of dementia  Lewy bodies and neurodegeneration affect brainstem and cortex   Pick’s disease and other frontal temporal dementias  Classification depends on histologic examination and is complicated www.indiandentalacademy.com
  137. 137. Parkinson’s disease: Clinical findings  Idiopathic Parkinson’s disease (vs. parkinsonism or parkinsonian syndrome), est 1% of population over 50 years of age  Tremor (rest)  Rigidity (cogwheel rigidity)  Bradykinesia (mask-like facies, loss of arm- swing)  Festinating gait (loss of righting reflexes) www.indiandentalacademy.com
  138. 138. Parkinson’s disease: Gross and microscopic findings Gross--loss of pigment in the substantia nigra  Microscopic--Lewy bodies with pigmented neuronal cell loss and gliosis   cortical Lewy bodies present in 80% or more of PD cases www.indiandentalacademy.com
  139. 139. Parkinson’s Disease www.indiandentalacademy.com
  140. 140. www.indiandentalacademy.com
  141. 141. www.indiandentalacademy.com
  142. 142. Other Extrapyramidal Movement Disorders   Parkinson’s disease: Hypokinetic Huntington’s disease: Hyperkinetic Choreiform movements  Intellectual decline   Multiple Systems Atrophy Parkinsonian features  Symptoms suggestive of olivopontocerebellar degeneration  Shy-Drager syndrome (parasympathetic dysfunction)  www.indiandentalacademy.com
  143. 143. Motor neuron disease  Amyotrophic lateral sclerosis (Lou Gehrig’s disease) Results in progressive weakness, eventually resulting in paralysis of respiratory muscles and death often within 2-5 years of diagnosis  Degeneration of upper (motor cortex) and lower (spinal cord) motor neurons  www.indiandentalacademy.com
  144. 144. Motor Neuron Disease    ALS: Adult form of motor neuron disease associated with both upper (brain) and lower (spinal cord) motor involvement Werdnig-Hoffman disease: The baby is weak (floppy) at birth. Lower (spinal cord) motor neurons are involved. Poliomyelitis: Lower motor neurons are destroyed. www.indiandentalacademy.com
  145. 145. Prion disease (Spongiform encephalopathy): Clinical findings     50-70 years old, rapidly evolving dementia, often with myoclonus and a characteristic EEG pattern (of repetitive sharp waves) Early symptoms include personality changes, impaired judgement, gait abnormalities, vertigo, In some patients cerebellar and visual abnormalities predominate Majority die w/in 6 months, frequently w/in 3 mo. www.indiandentalacademy.com
  146. 146. Prion disease: Pathogenesis     Transmissible but not “infectious” Prion protein, Prusiner--1997 Nobel Prize, (not a “slow virus”) PrPC -- produced normally in most cells --amino acid sequence is identical to the PrPSC --abnormal protein, the difference is in the secondary conformation (B-pleated vs alpha helical) PrPSC causes post-translational modification of PrPC Transmitted by direct inoculation (corneal transplants, dural grafts, pituitary products) www.indiandentalacademy.com
  147. 147. Prion disease: Gross and microscopic findings Gross appearance--may be normal due to short duration of disease  Microscopic appearance--vacuolation of neuropil, vacuoles are within nerve cell bodies and neuronal processes  cell loss and gliosis may be prominent  www.indiandentalacademy.com
  148. 148. Prion Disease www.indiandentalacademy.com
  149. 149. Summary: Neurodegenerative diseases  Dementia    Movement disorders    Alzheimer’s disease: common, amyloid hypothesis, plaques and tangles, gross brain atrophy Prion disease: rare, “transmissible” protein, rapidly progressive, vacuolar changes Parkinson’s disease: hypokinetic, loss of dopaminergic cells substantia nigra, Lewy bodies Huntington’s disease: choreiform movements, caudate atrophy, nuclear inclusions Motor neuron disease (ALS): Loss of upper and lower motor neurons, progressive over 2-5 years www.indiandentalacademy.com
  150. 150. Pediatric Neuropathology Developmental Abnormalities Neuronal Storage Diseases Familial Tumor Syndromes Perinatal Lesions/Infections Trauma: shaken baby syndrome www.indiandentalacademy.com
  151. 151. Developmental Abnormalities: Pathology   Organ induction (2.5-6 weeks): neural tube defects: anencephaly, spinal dysraphism, encephalocele, holoprosencephaly Neuronal (glial) migration (3-6 months): lissencephaly, microcephaly, polymicrogyria, agenesis of the corpus callosum Myelination (2 months-juvenile)  Synaptogenesis (20 week gestation-adulthood): trisomy 21, fragile X, cretinism In general, earlier insults cause more severe structural damage www.indiandentalacademy.com 
  152. 152. Organ Induction: Dysraphic Disorders  Failure of neural tube folds to close during development     Prenatal testing may reveal an elevated maternal serum AFP Folate deficiency: Folic acid supplementation prior to conception may reduce the incidence of neural tube defects up to 70% Neural tube defects range from small bony defects in the lumbosacral region (spina bifida occulta) to craniorachischisis. Myelomeningoceles occur most commonly in the lumbosacral region www.indiandentalacademy.com
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  156. 156. Neuronal migration disorders    Lissencephaly (smooth brain)/pachygyria (few enlarged gyri Polymicrogyria (many small gyri) Heterotopias (circumscribed collections) and dysplasias (disorganized lamination) Occur with other developmental abnormalities for example in patients with chromosomal abnormalities  May be the focus of seizure activity  www.indiandentalacademy.com
  157. 157. Seizures    Result from abnormal electrical activity of a group of brain cells and cause an altered mental state or tonic clonic movements. May be partial (focal) or generalized. In children seizures may result from neuronal migration abnormalities or from abnormalities acquired subsequent to brain damage (such as inflammation) A first time seizure in an adult would warrant an imaging study to rule out tumor or other structural abnormality www.indiandentalacademy.com
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  160. 160. Neuronal Storage Disease    Result from inborn errors of metabolism (deficient enzyme or abnormal lysosomal function) Progressive, poor treatment options (bone marrow transplant) Accumulation of metabolic products in the neuron  Tay Sachs disease  Neuronal ceroid lipofuscinosis  Glycogen storage disease www.indiandentalacademy.com
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  162. 162. Concentric Multilamellar membranous cytoplasmic bodies (MCB’s) www.indiandentalacademy.com
  163. 163. Familial Tumor Syndromes  Neurofibromatosis    NF-1: (most common) multiple peripheral neurofibromas NF-2: bilateral acoustic schwannomas and meningiomas Tuberous Sclerosis: subcortical and cortical hamaratomas(tubers) -Autosomal dominant -Tumor suppressor gene mutations -Cutaneous findings www.indiandentalacademy.com
  164. 164. Perinatal Lesions of the CNS Hemorrhage Hypoxic/Ischemic Infectious www.indiandentalacademy.com
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  167. 167. Congenital/Perinatal Infections TORCH      Toxoplasmosis Other: syphilis, TB, listeria monocytogenes; other viruses (VZV, HepB) Rubella (rare—immunizations) Cytomegalovirus, Chlamydia trachomatis Herpes simplex (usually type 2); HIV www.indiandentalacademy.com
  168. 168. Shaken Baby Syndrome     General: Violent shaking causes acceleration (shearing) injury of axons: diffuse axonal injury Neurologic: Blindness/mental retardation in infants less than 1 year of age. Present with apnea, seizures, lethargy, bradycardia, respiratory difficulty, coma. Pathology: Oculo-cerebral damage can occur without external evidence of head injury. Retinal and optic nerve sheath hemorrhage— ophthalmoscopic exam important Microscopic: Axonal spheroids www.indiandentalacademy.com
  169. 169. Summary: Pediatric neuropathology    Developmental abnormalities: Neural tube defects (anencephaly, spina bifida), migrational defects (mental retardation, seizures) Inborn errors of metabolism: Neuronal storage diseases and leukodystrophies Other: Familial tumor syndromes, hemorrhage, hypoxic/ischemic injury, shaken baby syndrome www.indiandentalacademy.com
  170. 170. Pathology of the Nervous System Introduction  Increased intracranial pressure  Vascular and circulatory disorders  Trauma  Infections  Tumors  Demyelinating diseases  Degenerative diseases  Developmental Abnormalities  www.indiandentalacademy.com
  171. 171. www.indiandentalacademy.com
  172. 172. The more people I meet… The more I like my dog www.indiandentalacademy.com
  173. 173. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com